See Figures 1 through 6
The canister cycles the fuel vapor from the fuel tank and, if carbureted, the carburetor float chambers into the intake manifold and eventually into the cylinders for combustion. The activated charcoal element within the canister acts as a storage device for the fuel vapors at times when the engine operating conditions do not allow efficient burning of the vapors.
The only required service for the canister is inspection at the intervals specified in the Maintenance Chart at the end of this section. If the charcoal element is saturated (possibly from carburetor flooding), the entire canister will require replacement. Label and disconnect the canister purge hoses, loosen the retaining bracket bolt(s) and lift out the canister. Installation is simply the reverse of the removal process. To check the canister:
- Label the vacuum lines leading to the canister.
- Remove the vacuum lines attached to the canister.
- Unfasten the retaining bolts from the canister.
- Lift the canister up and remove the lower hose attached to the unit.
- Inspect the case for any cracking or damage.
- Using low pressure compressed air, blow into the tank pipe (flanged end) and check that air flows freely from the other ports.
- Blow into the purge pipe (next to tank pipe) and check that air does not flow from the other ports. If air does flow, the check valve has failed and the canister must be replaced.
- Never attempt to flush the canister with fluid or solvent. Low pressure air 43 psi (294 kPa) maximum may be used to evaporate any vapors within the canister. When applying the air, hold a finger over the purge pipe to force all the air out the bottom port.
- No carbon should come out of the filter at any time. Loose charcoal is a sign of internal failure in the canister.